Scanning Kodak Elite Chrome 100 and Ektachrome 100 Plus

I scanned a couple of hundred Elite Chrome 100 slides (plastic mounts) for #2 son. I had the Nikon LS-40 ED (Coolscan IV) handy and used the latest edition of Vuescan (9.4.40). The results were superb, some of the best non-Kodachrome scans I have seen. This film from the late 1990s though was very 'grainy' or 'dye-cloudy' especially in some underexposed areas and had a magenta cast (variable between individual films) that was easily corrected. A 36-exposure Ektachrome 100 Plus (early 1990s) had a much cooler cast (very Ektachrome) but again produced excellent results from the twenty-year old transparencies. For both I had the IR dust removal on. 

Which Binoculars for Birding: Insights into Optical Design

Following up my post on the new Zeiss Victory SF binoculars, the most useful website for those seeking real information on the optical design of binoculars is that of Holger Merlitz who is Professor in the Department of Physics at Xiamen (Amoy to old China hands) University in China. His articles and papers are well worth reading and I have included links below to those of particular interest to this post in relation to the history of optical design, the introduction of intentional distortion and the characteristics of binoculars from different manufacturers.

The first major point to bear in mind is that the design of lenses for cameras differs (or should differ) from that for binoculars because the imaging system of binoculars includes the human eye which has its own distortions. The camera lens is aimed at the ideal of distortion free imaging; the binocular is aimed at the optimal image on the human retina, taking the binocular and eye as the integrated unit.

The history of the realisation that the unit to consider is binocular+eye is interesting and is outlined by Merlitz. Before 1950, optical designers tried to produce binoculars that, like camera lenses, were free of distortion (roughly defined as an absence of barrel or pincushion distortion). In 1949 Zeiss (Jena) picked up on the complaints of some army, presumably German, officers in two World Wars that when panned across the battlefield their binoculars or field glasses produced a strange effect that made them feel nauseous. As Merlitz puts it:

…appeared to display a rather strange kind of distortion, which became particularly obvious whenever that binocular was used for panning. The moving image appeared to roll over a curved, convex surface. This phenomenon, henceforth denoted globe effect, seemed to be absent with the static image, but it miraculously reappeared with the moving image each time the binocular was panned.

Koehler and Sonnefeld at Zeiss Jena, then in East Germany, suggested and demonstrated that this globe effect could be eliminated by introducing a degree of pincushion distortion into the binocular design. The human eye counteracts that pincushion bending of verticals and horizontals to send an image to the brain that is undistorted. Such a design of binocular would therefore be fine for both static spotting and panning. From the 1950s binocular manufacturers began introducing pincushion distortion. However, the degree of pincushion distortion employed can be noticeable and from about 2005 some manufacturers reverted to pre-1950 practice but in so doing exposed their customers to the globe effect and the feeling of nausea that it may induce.

More recently there has been renewed interest in the amount of pincushion distortion that should be added. Merlitz has tried to determine whether there is a point at which the globe effect is eliminated and noticeable pincushion distortion is minimised. I will not go into any detail of the geometry and trigonometry used to calculate theoretical levels of distortion here since they are fully described by Merlitz. suffice it to say that Sonnefeld, it seems, overestimated the degree of pincushion distortion required to overcome the globe effect. If k is the amount of pincushion distortion deliberately introduced and k = 1 is no distortion at all (termed the tangent condition and where the globe effect is evident), Sonnefeld suggested a value of 0 for k (the  angle condition). Other calculations from the work on human vision by another member of the Zeiss design team in the 1940s suggest a value of 0.5 (the circle condition).

More recent research by a group at Delft University in the Netherlands as well as that by Merlitz suggested that k should be between 0.6 and 0.8.

The more recent research brings out the second major point: there is variation between individuals on the value of k at which pincushion distortion can be perceived. For those interested, Merlitz shows Helmholtz checkerboards you can use to find your value of k (subject to variation in experimental conditions). Merlitz argues that the true average of k in the 56 people who responded to his request for help was around 0.7. Three of us here did the same study, finding values of 0.6, 0.7 and 0.8.

The major points throw up interesting challenges to the binocular manufacturer, as Merlitz points out:

Which consequences are to be drawn for the binocular manufacturer? With a choice of pincushion distortion near k=0.7, the majority of users would not complain about any globe effect. To be on the safe side, one might want to go a little lower, perhaps between k=0.6 and k=0.7, accepting a little bit of an extra pincushion distortion. In any case, the extremes should be avoided, namely values of k<0.5 (too much pincushion) or k>0.8 (too much of a globe effect).

and

It therefore appears that the ideal amount of distortion for handheld binoculars should be chosen between k = 0.6 and k = 0.8, a choice that would leave both the globe effect and the pincushion distortion (with the rolling eye) on a reasonably low level.

Merlitz also stated:

Binocular designers might also considering building oculars that would enable the user to modify the amount of distortion. In this way, the observer would be able to optimize the distortion characteristics of his instrument according to his own individual preferences and the particular mode of application.

As far as I know no manufacturer has yet done this and until one does, given the variation in different individuals, binoculars from one manufacturer may be more suitable for some individuals than those from another, depending on which k value is being incorporated in the optical design. If manufacturers stated the degree of pincushion distortion they have employed and retailers could test the k value of individual customers using Helmholtz checkerboards under proper test conditions, a better match might be achieved than by competitive birders buying binoculars for their brand badges—‘I’ve got to ‘ave Swarovskis ‘cos all my mates would laugh at me if I didn’t’, as I heard one checklist ticker say to another.

So what do we know of different manufacturers and their newer products. Well, here Merlitz helps again: From modern Nikons returning to pre-1950s undistorted optics and, therefore, the rolling ball effect when panning to the latest Zeiss Victory SF adopting a k value of 0.7, as recommended by Merlitz.

Of course there are many other optical and ergonomic factors in buying binoculars in a given price range, a sufficient number in fact to provide binocular nerds with hours and hours of discussion. But if you use binoculars to pan across the landscape, you need to read Merlitz and take note or you could end up with an the unpleasant rolling ball phenomenon and motion sickness if you choose a brand with undistorted optics.

---------------

1. These are all key pages in Holger Merlitz’s Website:

http://www.holgermerlitz.de

Merlitz, H. 2010. Distortion of binoculars revisited: Does the sweet spot exist? Journal of the Optical Society of America A 27, 50-57

http://www.holgermerlitz.de/globe/distortion_final.pdf

Distortion of the new Zeiss Victory SF: A paradigmatic shift on the binocular market?

http://www.holgermerlitz.de/newk/newk.html

2. Globe effect

http://en.wikipedia.org/wiki/Globe_effect

3. Oomes AH, Koenderink JJ, van Doorn AJ, de Ridder H. 2009. What are the uncurved lines in our visual field? A fresh look at Helmholtz's checkerboard. Perception 38, 1284-1294

Zeiss Victory SF Binoculars: Zeiss Are Really Fighting for Market Share

There is a lot of interest in birdwatching forums about the new Zeiss Victory SF binoculars. Zeiss, remember, went from being the brand everybody aspired to own in the 1950s and 1960s to also-rans in the competition with Leica and, later, Swarovski. My binocular tally saw a few more users of modern Zeiss binoculars over the past few years but this latest release, seen and used by only a chosen few, is an attempt to taker over the top end of the market. Zeiss describe them as: World's Best Birding and Nature Observation Binoculars.

It seems that Zeiss recruited a new designer—from Swarovski, and the new binoculars certainly bear more than a passing resemblance to Swarovskis. How much of the blurb in the press releases is hype only time will tell; the mere fact that they will be dearer than all the others will ensure healthy sales.

In looking up further information on the design features, this binocular-owning family has learnt a lot about the evolution of binocular optical design and I will follow up this post with the rest of that story.

http://www.zeiss.co.uk/sports-optics/en_gb/landingpages/world-s-best-birding-binoculars.html
http://lauraerickson.blogspot.co.uk/2014/07/falling-in-love-all-over-again.html
http://www.birdforum.net/showthread.php?t=284346

Amateur Photographer Subscriptions: Buy NEW Don't RENEW

I took out a two-year subsciption deal (two years for the price of one) for the print version of Amateur Photographer. The renewal notice arrived a few weeks ago. The renewal was for 20% off. Thinking that was a very small discount and wondering if their marketing department was following the insurance companies and banks in penalising brand loyalty, I looked up the new subscription rates. Yes, they were penalising loyalty, was the answer, as the comparison below shows:

2 years Renewal £218.32

2 years New £163.99

1 year Renewal £116.44

1 year New £86.99

Needless to say, I bought a new suscription and threw the renewal notice into the bin. Is there no end to the rip-offs in Britain pulled off by marketing departments offering automatic and semi-automatic renewals to customers?

What an Idiot

A readers writing congratulating the editor on the new look of Amateur Photographer (I see no improvement in the content so far, but that is by the way) also objected to the magazine reviewing a lens (Zeiss Otus) consisting in excess of £3,000. Is there any hope when a magazine is expected to be run on the politics of envy? Of course we need good reviews of top-of-the-range equipment, even if only to allow a judgement to be made of whether a particular improvement or feature is worth paying for. A few more readers might be retained if this magazine aimed higher. There are many amateur photographers out there with expensive but appropriate gear for what they want to do who despair at the never-ending reviews of low-level cameras that litter the magazines. Do magazines in the USA, where the magazines seem much more aspirational, have this problem?

A Bridge Superzoom NOT a DSLR for Birders

Bad advice given in photographic magazines soon gets picked up and batted back. A reader of Amateur Photographer (5 July 2014), Paul Robinson, soon pointed out that superzoom bridge cameras, in this case the Canon SX50 HS, were what birders use to photograph birds and that DSLRs for shots in the field were pretty useless.

The photographic magazines are really not staffed to provide reliable information on anything other than amateur 'pictorial' photography (as the meaning of 'pictorial' has changed over the years) and subjects covered by professionals in the world of commerce.

There is much better advice available online on almost anything in photography.

Photographic Magazines: Circulation Figures for 2013

The sales of photographic magazines continue to fall (see my post of 22 March 2013) along with virtually all magazines in the UK. Owners, editors and employess must be asking themselves, where will it all end?

Of those magazines audited by ABC, the year on year fall in circulation for photographic titles in the second half of 2013 was, starting with the worst: Digital SLR Photography -31.5%; Practical Photography -13.5%; Digital Camera Magazine -11.7%; Digital Photographer -11%; Amateur Photographer -9.9%; Digital Photo -5.6%. I do not know the circulation figures for other magazines that are not covered  by ABC, like Advanced Photographer.

The average change in sales of all UK magazines was -6.3%, so that photographic magazines, in general, performed worse than that.

Average sales for the monthly magazines ranged from 7,504 for British Journal of Photography (no figures available for year-on-year change) to 35,281 for Digital Photo. The average sale for the weekly, Amateur Photographer, was 15,505. 

Just as worrying for editors must be the result of the survey published in Amateur Photographer on 5 July. Yes, I know it is a self-selected group of readers responding but 52% said that they had been readers of AP for less than one year. No wonder the articles are at such a low level. But do the results of that survey also show that AP is not retaining its readership beyond the beginner stage, or that people stay in amateur photography, like most hobbies, for just a short time, or both? The ‘All New AP’ launched a couple of weeks ago is presumably an attempt to decrease or reverse the downward trend. Will it succeed? On its present showing I doubt it.

If magazine sales are falling, were are people getting their information? Even a basic photography book provides more information than a run of magazines but are people buying books? Or relying on the internet for information/misinformation?